Lower back pain

Since the second trimester I have been getting worse instead of better haha, my nausea has turned to sickness and now I have extremely bad pain, the other day it was so bad I couldn't hardly walk, it was in my legs, back and shoulders but my legs and shoulders have seemed to of got better but it's just this back pain I have had it over a week! Pain killers don't work, it's around my coccyx, lower back and hips, any good tips?